You don’t have to look far in the fitness industry to come across the term HIIT. In the last 10 years it’s become all the rage for reducing workout time, and increasing results. HIIT is a big shift from the conventional ‘cardio’ or aerobics boom of the 80’s. Where Aerobics and cardio tended to stay at a high intensity, or at least a sustained intensity for workout purposes, HIIT aims to break the intensity into chunks, to allow for recovery.
HIIT stands for High Intensity Interval Training. This means there are periods of work, followed by periods of rest. Just look at the picture at the top of this blog, and you’ll see how the clients heart rates went up over the threshold of 85% max heart rate (orange zone), and then back down below threshold, and into recovery at 65% max heart rate or lower (blue zone).
The benefits of HIIT are the reduced training time, the greater tissue hydration, lack of exhaustion, the greater release of anabolic hormones like testosterone and growth hormone, and the reduction of catabolic hormones like cortisol. Less training time means less mental exhaustion, because you are not trying to push through pain and sustain intensity. HIIT done right enables you to feel worked, yet energised post workout, rather than just smashed.
Heart rate training teaches us that there really is no differentiation between weight training and cardiovascular training any more. Any movement can fit into either category dependent on how you manipulate acute variables like speed, range of movement, force vector etc. HIIT allows for you to be creative with your movements ,and turn almost any movement into any heart rate zone.
MISSing the HIIT
The most overlooked factor in HIIT training, is that recovery is harder than work. Working with the general population, we see daily how many clients struggle with recovery from intensity. It’s so much harder for most people to get their heart rate DOWN, rather than getting it UP. This goes against what you might expect, but the reality is that exercise is a stress, and when we stress someone, generally their heart rate will go up, and the result is intensity. Anyone can do that. Recovery on the other hand, is the by product of an efficient system that is hydrated, nourished, intelligently moved, and has slept like a baby.
A happy and efficient system will recover well, and we see it take usually between 30-45 seconds for most clients. When recovery takes longer than this, we know that either the person is new to training and not yet conditioned, or that perhaps they are having an off day, and are probably not on top of lifestyle factors like sleep, nutrition, hydration, mental and emotional states and movement. Therefore there is extra stress compromising the ability of their body to bounce back from the HIIT
The Problem with HIIT
It only works if you actually HIIT! HIIT seems to be poorly understood by many. In order to achieve the benefits of HIIT you need to have the contrast between the two heart rate states, and include that second 'I" for Intervals. Aim to hit 85% max or what we call ‘gear 4’, and then drop back down into gear 2 at 65% or below.
So many gyms offer hit training that is simply one intense station after another, without recovery. In essence, this isn’t HIIT training. TABATA training where you work for 20 seconds on, 10 seconds off, is also not HIIT. Your heart rate will not recover in 10 seconds, and thus Tabata training is what we call HISS or High intensity Steady state.
Work + rest = success
When you perform HIIT with recovery intervals, and ensure your heart rate actually drops below 65% of your max heart rate, then you become more efficient. As you become more efficient, your heart rate can go higher, yet come down faster, meaning you can get more intensity and volume in your sessions, and faster results.